'91 Sammy runs rough

[Jim Blackwood]

Starts easily when cold. runs fine but has a rich miss at idle. As it warms up the miss gets worse until it dies. If allowed to idle warm before switching off it requires a flood clear to restart.

Would these be symptoms of a worn out injector perhaps? (Hope not those don't appear to be available anymore.) What's the best way to check?

At ambient both IAT and  ECT are in the 2500-3000 ohm range. As the engine warms up ECT resistance drops below 300 ohms so apparently that is OK.

Jim

[Jim Blackwood]

Did a test this AM. Started and ran the engine at about 3000 rpm until it cleared and ran smoothly then killed it with key and clutch. Restarted cleanly.Repeated but let it sit with the key on for a minute or so then started. This time it had a rich burble. Cleared and repeated. The test seems pretty conclusive to me. The injector leaks a bit. Not bad enough yet to cause any major problems but it won't be long before it does. So the injector needs to be replaced but there are none available. Used ones that are probably just as bad, can't be rebuilt due to wear.

Has anyone come up with a solution to this?

Jim

[fixkick]

Ok it floods that is never good
TBI air horn pip removed, eyes now see the 1 INJECTOR
rockauto has the parts. (they used to)
engine runs.
key off and all fuel ends, in second key is cut, or injector leaks
then key on 3 times (helper) and look at the injector
the tip may squirt tiny bit called the prime pulse.
but ends and the seals there both must not leak fuel ever. looking

so this is 91 8v engine and ECU.?
keep in mind the 90 TBI and older run a very special injector. as did the sammi.
the injector you buy must match the year TBI and year ECU.
EGRT is A16 to A24 per the schematic I posted above.

all my links went dead from 2007
not surprised.
rockauto shows none now.

leaving witchhunter and used parts off fleabay .

TBI injectors are not easy to find now, after 33 long years none are on the road, and makers now end sales of them.

http://fixkick.com/buy-parts#TBI

witchhunter did mine for $20
100% effective.
if he says its bad it is. for sure.





love that 10k resistor put in the best way possible nice job.
the MAP sensor must work. as must the 02. is this 3 wire 02?